Hiding in Augmented Reality

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Episode Transcript

Speaker 1 (00:03):
A breakthrough. An augmented reality does something that appears to
be simple but in fact is really tricky and lets
you hide a virtual object behind a real one. I'm
Jonathan Strickland, and this is tech stuff. Daily. Augmented reality
involves using some form of display or output device to

(00:23):
overlay digital information on top of the real data we
encounter out in the physical world. The typical representation of
this is some form of goggles or handheld display that
overlays computer generated imagery on top of a view of
our physical surroundings. This is just one type of augmented reality,
but it's a common one. There are numerous smartphone apps

(00:44):
that will let you look at the world through your
smartphone screen. You're looking at a live video feed captured
by the smartphones camera. The app will overlay some sort
of digital information on top of your live video view
of the world. It might be directions, such as an
arrow pointing to the indicating you need to make a
left turn to get to your pizza parlor. Or it
might be a virtual character in a game, perhaps a

(01:06):
big boss you have to battle before you can cross
the threshold of your local pizza parlor to get a
pepperoni slice. It's lunchtime. But one challenge a our developers
have faced is called occlusion. Occlusion in this sense is
all about an object blocking another object in the real world.
If one opaque object passes behind another, of course we

(01:28):
lose sight of it for a moment. For example, if
we play hide and seek and you go stand behind
a tree. When I look around, I'm not going to
see you, assuming of course you're using the tree to
block my view of you. And if you walk in
front of the tree, I'll see you, but I won't
be able to see the parts of the tree you're
covering up. This is obvious. We experience this every day,
so I know I'm not sharing anything new with you.

(01:48):
But now let's imagine we're using an augmented reality application
and hardware. We have to teach this system to recognize
the border of real world objects within view. It also
must recognize the relative distance of those objects from the camera,
as well as the virtual distance between the display and
the virtual object. Only then can such a system allow

(02:08):
for a virtual object to pass behind or in front
of a real one and have it reflected in the
display so it looks like it's really happening in front
of your eyes. This is a non trivial problem. A
research team at the University of Arizona's College of Optical
Sciences have a prototype display that tackles this issue. Their
display allows for a virtual object to be blocked by

(02:30):
a real world object. It also allows the virtual object
to block other objects that are behind it. That behind
was in air quotes, because obviously the virtual object isn't
really in the physical space at all. According to Professor
Hong Hua, the display takes the view of the real
world and with lenses, images it upon a spatial light modulator.

(02:52):
These are devices that can alter or modulate polarization, amplitude,
and phase of light beams. They often will modify the
intensity of a lightbeam, though more advanced ones can do
all sorts of funky things with light. The team used
a spatial light modulator to create a mask that blocks
out the bit of the real world that the virtual
object will inhabit. This modulated image is what then reaches

(03:16):
the display that you can see. One thing that's necessary
to make all this work is a depth sensor. Without
a depth sensor, the system cannot know which objects are
closer to the lens and which are further away. There
needs to be a way to measure that distance and
then calculate where a virtual object should fall based upon
that objects virtual distance from the viewer. This is a

(03:38):
big jump from just overlaying a digital image on top
of a video view of the world. This is incorporating
computer generated imagery into a real environment as if it
too were just as real. Law says that it will
likely be sometime before we see this capability built into
consumer headsets. She says her team's solution wasn't exactly sleek
and sexy. They were just trying to get a system

(04:00):
that worked. Refining that system into something more consumer friendly
will take some time to get it down to a
format that might fit in, say a pair of special
glasses will take even more time, but the foundation is there.
To learn more about augmented reality, mixed reality, and all
sorts of other types of reality. Subscribe to the Tech
Stuff podcast every Wednesday and Friday. I look at big

(04:23):
topics and tech and really explore how they work and
why they're important. I'll see you again soon.